The organization Black Sun-introduced in Shadows-is still heavily in canon; however, Xizor not so much (although his species are seen representing Black Sun with a similar outfit in "Clone Wars").
I don't think Disney has touched too much of the ESB/ROTJ gap where Shadows takes place, apart from the preparations for Endor in "Moving Target" and "Lost Stars". Although it seems that Marvel's monthly is starting to move towards ESB a lot more now, so we'll see I guess.